1. Field of the Invention
The present invention relates to a method for forming a low dielectric layer of a semiconductor device, and more particularly to a method for forming a low dielectric layer of a semiconductor device capable of preventing a film from being delaminated at an interfacial surface due to film stress or adhesion fault, after processes for forming a low dielectric layer and a low resistance metal wiring have been completed to achieve semiconductor devices operated at a high speed.
2. Description of the Prior Art
As semiconductor devices have been highly integrated, characteristic resistance of a semiconductor device caused by an RC time delay and signal interference becomes an issue. For this reason, an integration technique for lower dielectric layers and low resistance metal wirings has been studied and developed.
Recently, as a low dielectric layer formed by using polymer material has been developed, an integrating process for the lower dielectric layer with a metal wiring, such as W, Al or Cu, has been actively studied.
The low dielectric polymer layer includes a carbon-hydrogen compound and oxygen added to the carbon-hydrogen compound.
However, the low dielectric polymer layer is formed with a porous structure and has hardness lower than hardness of an oxide layer, so adhesion force of the low dielectric polymer layer is lowered when stress is applied thereto.
For this reason, as shown in FIG. 1, a next process, such as a process for forming a SiON layer 15 used for a hard mask, a metal diffusion barrier 17 and a tungsten layer 19, has been carried out after forming the low dielectric polymer layer, or when a reliability testing process is carried out after semiconductor fabricating processes have been carried out as shown in FIG. 2, a succeeding insulation layer is delaminated from the low dielectric polymer layer.
Such delamination of the insulation layer is derived from a lack of adhesion force at an interfacial surface between insulation layers and causes a decrease of a yield rate of semiconductor devices.